Answer: less than 12.75.

For any dataset where the values are not equal, the harmonic mean will be less than the geometric mean (which, in turn, will be less than the arithmetic mean). Here, the arithmetic mean is 13.25, and the geometric mean is 12.75—so the harmonic mean must be less than 12.75. It is worth noting that all three means are equal if every value in the dataset is the same. **Key Concept:** The relationship between arithmetic mean (AM), geometric mean (GM), and harmonic mean (HM) for positive numbers is: HM ≤ GM ≤ AM, with equality holding only when all values are equal.

Author: LeetQuiz Editorial Team